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Angaben zur Quelle [Bearbeiten]

Autor     Hassan Mahfuz, Mujibur R. Khan, Ashfaq Adnan, Mohammad M. Hasan, Vijaya K. Rangari, Vinod Dhanak, Shaik Jeelani
Titel    ADVANCES IN NANOSCALE REINFORCEMENT OF TEXTILE POLYMERS
Jahr    2008
Anmerkung    Proceedings of the 4th BSME-ASME International Conference on Thermal Engineering, 27-29 December,2008, Dhaka, Bangladesh
URL    http://bsmeicte2012.iutoic-dhaka.edu/proceedings/4th-bsme-asme-icte-2008/Final%20Papers/01%20Keynote_lectures%2001/Keynote-Paper-5.pdf

Literaturverz.   

no
Fußnoten    no
Fragmente    3


Fragmente der Quelle:
[1.] Mrs/Fragment 029 11 - Diskussion
Zuletzt bearbeitet: 2015-04-19 18:53:35 WiseWoman
BauernOpfer, Fragment, Gesichtet, Mahfuz et al 2008, Mrs, SMWFragment, Schutzlevel sysop

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Untersuchte Arbeit:
Seite: 29, Zeilen: 11-23
Quelle: Mahfuz et al 2008
Seite(n): 27, Zeilen: 27 ff.
Polyamide’s toughness, low coefficient of friction and good abrasion resistance make it an ideal replacement for a wide variety of applications, replacing metal and rubber. The amide groups of polyamide are very polar, and hydrogen bonds can form between them. Because of these, and because the polyamide backbone is so regular and symmetrical, polyamides are often crystalline, and make very good fibers [107]. When polyamide is spun into fibers, the long chainlike macromolecules line up parallel to each other. The amide groups on adjacent chains then form strong bonds with each other called bridged hydrogen bonds. These hydrogen bonds hold the adjacent chains together, making polyamide yarn strong. When polyamide 6 polymerizes, the amide link present in caprolactam (starting monomer for polyamide 6) opens up and the molecules join up in a continuous chain, providing an ideal mechanism for interacting with nanoparticles. On the other hand, silica particles are formed by strong covalent bonds between silicon and oxygen atoms by sharing their electron pairs at the p orbital. The surface bound OH groups on the silica surfaces may also form stable bonds with polyamide during polymerization.

[107] H. Mahfuz, M. Hasan, V. Dhanak, Nanotechnology 19 (2008) 445702 (7pp)

Nylon’s toughness, low coefficient of friction and good abrasion resistance make it an ideal replacement for a wide variety of applications replacing metal and rubber. The amide groups of nylon are very polar, and can hydrogen bond with each other. Because of these, and because the nylon backbone is so regular and symmetrical, nylons are partially crystalline, and they make very good fiber [22-26].[...] When nylon is spun into fibers, the long chain-like macromolecules line up parallel to each other. The amide groups on adjacent chains then form strong bonds with each other called hydrogen bonds. These hydrogen bonds hold the adjacent chains together, making nylon yarn strong. When nylon-6 polymerizes, the amide link present in Caprolactam (starting monomer for nylon-6) opens up and the molecules join up in a continuous chain providing an ideal mechanism for interacting with nanoparticles. On the other hand, silica particles are formed by strong covalent bonds between silicon and oxygen atoms by sharing their electron pairs at the p orbitals. In addition, the surface bound OH groups on silica surfaces offer an opportunity to form stable bonds with nylon or any functional group during polymerization.

[22] Kohan M. I, editor. Nylon Plastics, John Wiley & Sons, New York 1973, p.3-4.

[23] Fornes TD, Paul D.R., Polymer, 44, 3945, ., 2003

[24] Kim, Young, Materials Research Society Symposium - Proceedings, 2002, V740, 441

[25] Zhang, Wei-De, Macromolecular Rapid Communications, 2004,V 25, n 21, 1860.

[26] Jin L, Bower C, Zhou O. Appl Phys, 1998 Lett, 73, 1197.

Anmerkungen

The source is mentioned (the source used for documentation here and the source given both contain the section used here). It does not become clear, however, that the entire passage has been taken from the source.

Sichter
(Hindemith), SleepyHollow02

[2.] Mrs/Fragment 132 07 - Diskussion
Zuletzt bearbeitet: 2015-04-19 18:57:00 WiseWoman
Fragment, Gesichtet, Mahfuz et al 2008, Mrs, SMWFragment, Schutzlevel sysop, Verschleierung

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Untersuchte Arbeit:
Seite: 132, Zeilen: 7-10, 11-18
Quelle: Mahfuz et al 2008
Seite(n): 6, Zeilen: 6. 38 ff.
Three basic bonds of polyamide 6, i.e. amide N–H at 3297 cm-1, hydroxyl O–H at 2800–3000 cm-1, and carbonyl C=O at 1637 cm-1 were of primary interest. It is seen in Figure 8.11(b) that IR absorbance for each of the three basic bonds has increased significantly, characterized by their sharper and higher peaks. Higher peak and larger area under the curve corresponds to higher absorption of light energy of the chemical bond concerned. In other words, the IR absorbance is a direct measure of the interaction with the molecular environment, indicating that SiO2 reinforcement into polyamide was responsible for such an increase. On the other hand, after functionalization of SiO2 particles, i.e. in Figure 8.11(c), it is seen that the wave number of the three basic bond are maintained, while in addition, a siloxane Si–O–Si bond at 1090 cm-1 is formed which was not seen with Figures 8.11(a). This is what was expected from functionalization; establishing a continuous covalent linkage across the particle (silica) and polymer (polyamide 6) interface [107].

[107] H. Mahfuz, M. Hasan, V. Dhanak, Nanotechnology 19 (2008) 445702 (7pp)

Three basic bonds of nylon 6, i.e., amide N-H @ 3297 cm-1, hydroxyl O-H @ 2800-3000 cm-1, and carbonyl C=O @ 1637 cm-1 were of primary interests. It is seen in Fig 8.b that IR absorbance for each of the three basic bonds has increased significantly characterized by their sharper and higher peaks. The IR absorbance is a direct measure of bond strength indicating that SiO2 reinforcement into nylon was responsible for such increase. On the other hand after functionalization of SiO2 particles, i.e., in

[page 7]

Fig 8.c it is seen that three basic bond strengths are maintained, while in addition, a siloxane Si-O-Si bond @1090 cm-1 is formed which was not seen with Fig 8.a or 8.b.This is what we expected from functionalization; establishing a continuous covalent linkage across the particle (silica) and polymer (Nylon 6) interface.

Anmerkungen

The source is not mentioned. Possibly the passage can also be found in reference [107] (to be checked), but even if this was the case, it would not become clear that the whole documented passage is taken from the source.

In particular, it does not become clear that what is described are not experiments of M . R. S., but of other authors.

Sichter
(Hindemith), SleepyHollow02

[3.] Mrs/Fragment 133 01 - Diskussion
Zuletzt bearbeitet: 2015-04-19 19:02:18 WiseWoman
Fragment, Gesichtet, Mahfuz et al 2008, Mrs, SMWFragment, Schutzlevel sysop, Verschleierung

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Untersuchte Arbeit:
Seite: 133, Zeilen: figure
Quelle: Mahfuz et al 2008
Seite(n): 7, Zeilen: figure
Mrs 133a diss2.png

Figure 8.11 FTIR spectra (a) pure PA6 fiber, (b) PA6 fiber with 0.5% silica, (c) PA6 fiber with 0.5 % modified silica.

Mrs 133a source2.png

Fig 8: FTIR Spectroscopy – (a) neat nylon 6, (b) nylon 6 with 1wt% silica, and (c) nylon 6 with 1 wt% functionalized silica.

Anmerkungen

The source is not mentioned here. The reader gets the wrong impression that he is presented with measurements of M. R. S.. Note that on the previous page 132, line 3, one reads:

"8.4.2. Results and discussion Part 2: nanocomposite fiber
8.4.2.1. FTIR characterization of nanocomposite fibers
In order to determine the development of various functional bonds during polymerization, FTIR spectroscopy was performed. An FTIR experiment with polyamide 6 and with functionalized silica nanoparticles is shown in Figure 8.11."

Note also the caption: M. R. S. claims that slightly different fibers have been analysed in the dissertation as compared to the source.

Compare also the text before this figure on the previous page, which has also been taken from the source (and where the source is mentioned): Fragment 132 07

Close-ups of the green curve hitting the x-axis above:

Mrs 133a diss3.png Mrs 133a source3.png

Note:

  • graph in the dissertation is far more blurred than in the source (and also far more than other graphs in the dissertation)
  • The green curve touches the x-axis above in the same way in the dissertation as in the source --> a strong indication that the two graphs in fact are identical.
  • The graph titles are not part of the blurred bitmap of the graphs, but have been added separately, they are sharp and selectable as writing in the PDF version of the dissertation.
Sichter
(Hindemith), SleepyHollow02

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